It's pretty much over the range - I know for sure it afflicts pre-1997 issues, not sure about the Bridges series or not yet. However, I don't live in the UK, so I don't see as many of them as others here that would be able to give a better view.
OK, I found several pound coins out of a lot of 100 that looked like they deserved a closer look, then looked at the Royal Mint site that was provided by andyscouse. The dates all match up with the designs and inscriptions. However, a couple of the coins (1983, 1985) appear to be rather banged up, and the edge inscription appears to be weak in places. A third coin (1985) is also banged up, and while its edge inscription is proper and strong, the obverse and reverse are not perfectly aligned. So, where do I go from here to make a further diagnosis?
the third could be genuine as the alloy used for the pound coins becomes banged and gouged fairly easily, when the edge inscription appears weak this again could be a minting error as some £2 coins have come to light with weak edge inscriptions as well. the style of font in the edge lettering is a give away as the official style is semi itallic whilst most forgeries are roman font.
On the 1985 coin with the misaligned die, there does not appear to be anything wrong with the edge inscription-- it is in semi-italic font, perfectly centered on the edge, and there do not appear to be any problems with any of the letters. But the obverse and reverse dies are misaligned by 30 to 35 degrees. On the 1983 coin, the second T in TUTAMEN is missing the right half of the horizontal line, and the A next to it is missing the right part of the right serif. I have also found a 1984 coin where NEMO is slanting downward (the N is much closer to the top than the bottom), but the rest of the inscription seems to be fairly well centered.
I have a counterfeit US nickel I pulled from circulation. Dated 1948 and made of tin or something similar. I figure teenager in a 1950's shop class.
A few responses ago said the fakes are made of lead and then coated. This sounds like it should be a public health issue too. Separately, I'm surprised there aren't a glut of fake lead US $1 coins coming over from China. I know the profit margin would be slim, but I bet some young entrepreneur will do it. Your average cashier in the US would have no clue. I spent some 50 cent pieces the other day and the cashier asked me if they were dollar coins. Of course I told her they were half dollars, but it would have been very easy to lie to her. I bet you wouldn't even need the right design on a US dollar coin to spend it in most places.
A fairly common trait is that the edge inscriptions on fake £1 coins range from moderate to downright awful! So, missing letters, or letters that aren't punched correctly could well indicate a fake. Also note that with the new Maklouf portrait in 1985, ALL obverses for coins of this date are much more weakly struck than in following years. That, coupled with the alloy's weakness (compared to CuNi, for example), means that 1985 coins tend to be a lot more 'worn', because their relief was lower to start with. No guide, however, seems to note this fact. I think also that the Maklouf portrait in general is more prone to wear than the Machin and IRB protraits.
The problem would be getting them unobtrusively into circulation. Everybody in England uses pound coins, so they don't pay much attention to them in a transaction. Almost nobody here uses dollar coins, so they pay more attention. The presence of fakes would become quickly and widely known, and they would be driven from circulation.
OK, so the '83 and '84 go into my fake coin collection, whilst the '85 is probably genuine, even though the reverse is out of line with the obverse by about 30-35 degrees. If the '85 is, indeed, genuine, with such a misalignment of obverse and reverse would it be considered an error coin?
It looks like the video on the OP is now active for all regions (previously, it could only be viewed by BBC subscribers). It talks about the edge lettering (especially the cross) and the orientation of the front and back as being diagnostics. I wonder if anyone is collecting the fakes and documenting the varieties. This is also going to throw a wrench into collecting pound errors.
I would love to see scans of those fakes. After doing some research on other sites, I put together the following guide to detecting fake £1 Coins: http://mycoins.co/counterfeit-british-1-coins
Oh, my gosh-- This is almost surreal. I took another look at the pound coins I had set aside, and found at least 3 more that might qualify as fakes-- so far. Sometimes the edge lettering contains squiggly lines, or is uneven or otherwise less than perfect. On a couple of coins, there appears to be either corrosion, or the coating is wearing off. I wonder how many more fakes I'll find? A note about these pound coins: They have been accumulated by me over the years from foreign coin grab bags that I have bought at coin shows here in Japan. The bags are assembled by a local charity from coins that they have collected from donation boxes strategically placed in various international hotels and airports in Japan. Japanese travelers returning from overseas who have a pocketful of foreign coins will often drop their foreign coins into one of these boxes.
I think the two on the left side of the bottom row may actually be genuine. Some of the others may be genuine as well, but the vast majority of these have some problem or problems that, according to the diagnostics presented in this thread and referenced web sites, indicate that they are in all likelihood fake. If I can get some good scans of the edge lettering, I'll post them as well.
as an update to this thread i did a random check on my change today and out of 10 pound coins 3 were counterfeit......it really is becoming an epidemic..........
Germany too but Euros this time Pounds a little bit ff-topic:but now 1$ Euros In last week Coin World 4/25/2011 they reported the German Police found a counterfeiting operation that netted 8.5 million 1$ euros coins ready to be shipped.and 1/2 of a ton metal stock for there coin pressing machines they had.